Driver Attitudes and Behaviors at Intersections and Potential Effectiveness of Engineering Countermeasures

CHAPTER 2. METHODS FOR CONDUCTING THE FOCUS GROUPS

OVERVIEW

The objective of the focus groups was to identify driver attitudes and behaviors about intersection safety and to assess the likely impacts of new or existing infrastructure-based technologies/countermeasures.

Four focus groups were conducted at each of three test sites: Washington, DC; Chicago, IL; and Seattle, WA. At each site, the four groups corresponded to the age/gender characteristics identified as important to this project. The groups were:

18- to 35-year-old female drivers only.

18- to 35-year-old male drivers only.

35- to 55-year-old drivers of both genders.

65+-year-old drivers of both genders.

At each site, the focus groups took place over two separate evenings, with two focus groups conducted per evening. A total of 119 individuals participated in the focus groups.

Using the criteria described in appendix A, the project team screened focus group participants to ensure that relevant points of view were adequately represented in the groups (e.g., drivers who have difficulties making left turns, red-light runners, younger drivers, older drivers, etc.).2 The content of the focus groups addressed issues related to driver attitudes and beliefs about safety in signalized and unsignalized intersections both in the general context of approaching intersections and in the specific context of high-risk intersection scenarios (e.g., stale yellow light, left turn into traffic, etc.). Also addressed in the focus groups were respondent opinions about the potential effectiveness of specific intersection countermeasures. Take-home surveys were distributed to focus group participants to get additional information not covered in the focus group discussions. Finally, the researchers analyzed and summarized the results of the focus groups presented in this report.

Organizing and scheduling focus group facilities, including audiovisual capabilities.

Conducting the focus groups, including rescreening and take-home surveys.

Analyzing and providing a topline summary of the focus group discussion highlights.

Each of these activities is described in more detail below.

2The participant screener shown in appendix A reflects some minor changes from the screener guide presented in the original workplan for the focus groups.

Selection of Focus Group Discussion Scenarios

The first activity was to determine the scope of the intersection safety investigation. There are several different characteristics of intersections (e.g., signalized, unsignalized, urban, rural, traffic volume, etc.) that affect driver behaviors at intersections in addition to different types of unsafe activities that drivers can perform at various intersections (e.g., red-light running, failure to yield, left turns across traffic, etc.). It is not possible to investigate all of these combinations given the limited time available to conduct the focus groups, so the project team selected a subset of these aspects for discussion in the focus groups.

Selection criteria were based on crash data and the availability of infrastructure-based countermeasures. In particular, an analysis of crash types at intersections using 1998 GES data conducted by Najm et al. indicates that the most common crash types involve straight crossing path crashes in signalized (SCP/SI) and unsignalized (SCP/UI) intersections, in addition to left turn across path/opposite direction (LTAP/OD) crashes at signalized intersections, and left turn across path/lateral direction (LTAP/LD) crashes at unsignalized intersections (see table 1).(1) Three of these crash types were selected as scenarios, including SCP/SI, LTAP/OD (signalized intersection), and LTAP/LD (stop-controlled intersection), based on maximizing the diversity of situational factors and countermeasure types that could be presented to focus group participants. In addition to these crash types, a scenario based on rear-end crash situations was also added because of the high prevalence this type of crash at intersections. According to 1993 GES data, rear-end crashes at intersections comprise approximately 12 percent of all roadway crashes.(2)

Table 1. Relative frequency of intersection crossing-path crashes.(1)

Traffic Control Device

Crossing Path Precrash Scenarios (%)

LTAP/OD1

LTAP/LD2

LTIP3

RTIP4

SCP 5

Signal

20.48

4.74

1.34

1.79

16.28

Stop Sign

1.43

11.45

3.04

2.59

21.11

No Control

8.41

2.33

0.89

0.98

3.13

1 Left turn across path/opposite direction

2 Left turn across path/lateral direction

3 Left turn into path

4 Right turn into path

5 Straight crossing path

The specific situational factors for each scenario were also selected so that they took into account the most common causal factors for each crash type.(2) For example, because “tried to beat signal” and “violation of signal” were identified as major causal factors in SCP/SI crashes, the corresponding scenario involved a yellow light dilemma-zone situation. Similar attempts were made to incorporate the major causal factors into the other scenarios as well. Table 2 shows descriptions of the individual scenarios.

Table 2. Focus group discussion scenarios.

SCENARIO

DESCRIPTION

SCENARIO 1

SI/SCP (Red-light running): Approaching a signalized intersection at speed, the light turns yellow; driver is far enough away from the intersection that he/she can stop if he/she brakes hard, but is likely to enter the intersection on an early red if he/she accelerates.

SCENARIO 2

LTAP/OD (Left turn in traffic): Stopped in the middle of an intersection, waiting to make a left turn on a busy street; an oncoming car is also waiting to turn left and makes it difficult to see other vehicles approaching in the next lane. There is no dedicated turning lane and no dedicated turn signal; cars are waiting behind to also turn left (or go straight).

SCENARIO 3

LTAP/LD (Left turn at stop sign): A vehicle is stopped on a minor road with a stop sign, waiting to turn left onto a major road (that has no stop sign); a consistent flow of vehicles going at high speeds is crossing in both directions on the major road.

SCENARIO 4

Rear-end crash: Approaching an intersection at speed, the car in front stops suddenly when the light changes to yellow; the driver needs to slam on the brakes to avoid a rear-end collision.

SELECTING THE TEST SITES

As noted above, four focus group sessions were held at each of three test sites. The selected sites included Washington, DC, where the contractor has a state-of-the-art facility; Seattle, WA; and Chicago, IL. Site selection was based on criteria that considered access to required participant populations, varying market size and existence of relevant intersection features of interest (e.g., urban and rural intersections, etc.), and cost impact of conducting the focus groups. Another consideration was that the sites also provide a range of atmospheric and road-traction conditions. For example, respondents from Chicago, IL, were more likely to be familiar with driving in snow and ice conditions, while respondents from Seattle, WA, were more likely to be familiar with driving under a variety of precipitation and fog conditions.

The Washington, DC, site served as the first focus group location. This choice allowed FHWA personnel and project staff to observe the initial sessions in the contractor’s facilities and to provide important feedback on the conduct and direction of the focus groups. Based on these initial sessions, the researchers made minor changes to the Moderator Guide used to conduct each focus group session. Appendix B provides the updated Moderator Guide.

The core of any focus group project lies in: (1) developing and fine-tuning tools to most efficiently recruit participants with desired characteristics, and (2) implementing techniques to gather the best possible data. Appendices A and B are the final versions of the Participant Screener and Moderator Guide. These items are described below.

Participant Screener

The participant screener for this task used questions to identify drivers that reported either intentionally or unintentionally entering an intersection on a red, in addition to those who reported encountering left-turn situations where they had to engage in risky driving (see appendix A). Additionally, previous research indicates that factors such as driver age, gender, marital status, and having young children present affect driver intersection behaviors, such as red-light running and left-turn making. (See references 3, 4, 5, and 6.) These factors were also considered while developing the participant screener.

Within each group, participants were mixed on certain criteria such as marital status, having children, and red-light running (e.g., at least four, but no more than six red-light runners per group). This mix ensured that the participants represented a sufficient diversity of opinions on the relevant topics. In addition, past focus group experience indicates that separating the focus groups this way is effective in creating enough homogeneity among age and sex to elicit participation from all respondents and ease the social pressures associated with focus group dynamics. This factor is particularly true for respondents under the age of 35, when men and women should be in separate groups whenever possible.

Moderator Guides

Appendix B shows the final Moderator Guide that provided a general sense of the focus groups’ content including timing of various topics, information flow, planned scope, optimal external stimuli, and specific topic questions for the focus group discussions. The Moderator Guide covers four general discussion sections:

Introduction-Moderator and participant introductions (first name only) along with disclosures and a balanced and appropriate explanation of plans and expectations for the next 2 hours.

Warmup-The moderator directs the participants to discuss general issues about the topic and establishes a rapport with the group.

Exercises-A variety of easel exercises, including projective techniques, are used to gain respondents’ input about the intersection scenarios and corresponding countermeasures.

Closing-The moderator provides the group members with an opportunity to share information about any topic that they may have previously omitted.

The “Exercises”portion of the Moderator Guide contained the key discussion topics. These covered red-light running, making left turns at signalized and unsignalized intersections, and rear-end-crash situations. For each of these scenarios, the moderator’s objective was to obtain participant opinions regarding:

General views about specific intersection scenarios.

What drivers see as the perceptual, decisionmaking, and psychomotor requirements in each scenario. Additionally, how do these requirements combine to produce highly demanding or highly difficult driving episodes?

The potential effectiveness of various countermeasures in improving safety and the perceptual, decisionmaking, and psychomotor challenges identified in each scenario.

In addition, for red-light running behaviors, some of the beliefs, attitudes, knowledge, etc., underlying the risky actions were probed in further detail. The guide was designed with open-ended questions to gain optimal respondent input while maximizing objectivity and minimizing predictability. Probes and other information gathering techniques were altered in each scenario.

The countermeasures investigated in the Moderator Guide were drawn primarily from the National Cooperative Highway Research Program (NCHRP) guides for addressing signalized and unsignalized intersection collisions.(7,8) The emphasis was on selecting infrastructure-based countermeasures that could provide fruitful avenues for future research.

Other Materials (Countermeasures)

The focus group materials included written and graphic descriptions of the intersection scenarios and corresponding countermeasures. Table 3 shows a list of the countermeasures presented in each scenario. The graphics presented in the Results chapter below (figures 9 through 17) show how the countermeasures looked to drivers and include schematic layouts to coincide with each scenario that demonstrate how the countermeasures function and their layout in the roadway environment. Clearly written explanations of how the countermeasures worked in addition to any impacts they would have on the traffic flow accompanied the graphics. Key visual aspects (e.g., flashing lights) that may not be evident from the graphics were also explained to the focus group participants. Most countermeasures were selected for particular scenarios if they addressed one or more of the primary driver-related causal factors identified with each crash type.(2) If data were available, the potential effectiveness of individual countermeasures was also considered.(9)

Table 3. Scenario countermeasures for the focus groups.

Scenario 1: Red-Light Running

1. Red-light cameras

2. High-visibility traffic lights

3. Advance traffic light warning signs

4. Intersection collision warning systems

Scenario 2: Left Turns at Busy Intersections

1. Protected left-turn lights

Scenario 3: Turning Left on Major Road with Moderate Traffic

1. Automatic gap detection

2. Synchronized adjacent traffic signals

Scenario 4: Rear-End Crashes

1. Intersection rumble strips

2. Improved skid resistance

To reduce the chances of biasing the participants’ evaluations of the relative potential effectiveness of individual countermeasures, the project team attempted to match the level of description and detail for all countermeasures, in addition to presenting the information in a common format where possible.

Take-Home Survey

The researchers developed a brief take-home survey (shown in appendix C) to obtain participant responses about relevant intersection activities that could not be addressed-because of time restrictions-during the actual focus groups. The questionnaire included 12 Likert scale and open-ended questions. All questions addressed the following scenario: “These questions are about the driving situation discussed in the group where the light turns yellow just as you approach an intersection. Specifically, you have enough time to stop if you brake quickly; otherwise the light is likely to turn red while you are in the intersection unless you speed up quite a bit.”

A late-yellow/early-red scenario was selected rather than a clear red-light-running scenario because the project team anticipated that not enough of the participants recruited would be able to report running red lights with sufficient frequency to yield correlations to behavioral factors. Thus, the late-yellow/early-red scenario was used instead of red-light running.

The moderator encouraged respondents to complete this questionnaire either before they left the focus group location or as soon as they returned home, while thoughts generated in the group were still fresh in their minds. As described in more detail in chapter 3, the return rate for the take-home surveys was 70 percent.

IDENTIFYING, SCREENING, AND SCHEDULING RESPONDENTS

Participant Sources/Pools

All participants were identified, screened, and scheduled using databank recruiting provided by local research organizations. In each of the three cities where focus groups were to take place, the project team paid research organizations to recruit and schedule focus group participants. Each of these organizations has in-house demographic information on individuals who have expressed a prior willingness to participate as respondents for various research topics. Research assistants at these organizations used the participant screener provided by the contractors to identify participants that meet the selection criteria for the specific focus group sessions.

Scheduling Respondents

Recruiting organizations contacted candidate participants by telephone, provided them with a general description of the task, offered stipends, screened according to the procedures detailed in the participant screener, and assigned them to a focus group session if appropriate. Identifying, screening, and scheduling respondents ran from September 20, 2004, to October 15, 2004.

With the exception of the first focus group, 12 respondents were scheduled for each group to ensure that 8 to 10 were present for the actual focus group. For the first focus group in Washington, DC, 14 respondents were recruited to ensure that the maximum number of 10 were present. This strategy was ultimately helpful because it provided the project team with an understanding of how the maximum number of participants as part of the initial group evaluation impacted the timing of the groups.

ORGANIZING AND SCHEDULING FOCUS GROUP FACILITIES, INCLUDING AUDIOVISUAL CAPABILITIES

State-of-the-art research facilities were used for the Washington, DC, and Seattle, WA, focus groups. Facilities included focus group rooms wired with the necessary audio and video recording capabilities and a one-way mirror that provided a life-size view of the focus groups from an adjacent room and allowed observation of facial expressions and other nonverbal responses. In addition, facilities had the necessary waiting rooms and other amenities to ensure the comfort of participants, observers, and moderator. An appropriate facility was also arranged for the Chicago, IL, focus groups.

CONDUCTING THE FOCUS GROUPS

As participants arrived for each focus group, they were briefly rescreened as a final quality control measure to ensure they met all participation criteria. The first focus group in Washington, DC, was scheduled in the early afternoon to debrief, clarify, and crystallize the meaning of what had transpired. In the debriefing, the project team assessed the flow, timing, countermeasure coverage after the scenarios, and whether the Moderator Guide met all technical objectives. The project team then made all necessary adjustments before the second focus group met. Appendix B reflects these adjustments to the Moderator Guide.

The focus groups were conducted using the content and flow presented in the Moderator Guide in appendix B and the countermeasure descriptions in figures 9 through 17. The researchers videotaped participant responses, and collected handwritten notes taken by both the moderator and the observer.

Across the 3 focus group locations, a total number of 119 individuals participated in the task B.1.2 focus groups. Table 4 below shows the number of participants by location and gender/age characteristics.

Table 4. Number of focus group participants as a function of location and age/gender characteristics.

AGE/GENDER CHARACTERISTICS

Table 4. Number of focus group participants as a function of location and age/gender characteristics.

Washington, DC

Chicago, IL

Seattle, WA

18- to-35-year-old females

8

10

10

18- to 35-year-old males

10

10

10

35- to 55-year-old males and females

10

10

10

65+-year-old males and females

11

10

10

Once participants completed the focus group and were dismissed, they were paid $75 each and given the take-home survey to complete on their own time, along with a self-addressed stamped envelope to mail the survey back to the contractor.

ANALYZING AND SUMMARIZING THE HIGHLIGHTS OF THE FOCUS GROUP DISCUSSIONS

The raw data of the analyses were the words, phrases, sentences, and nonverbal responses of the focus group participants. Project staff looked at all data (tapes, notes, postsession summaries) for patterns emerging from the data. To analyze and summarize the focus group discussions, both the moderator and observer:

Took notes during each of the focus group sessions.

Independently developed summaries of each focus group session organized around the key questions/issues addressed during each session.

Contributed interpretations and inferences; pointed out any possible biases and contradictions.

Reviewed taped transcripts of the focus groups.

Compiled key findings in a topline results summary.

The take-home surveys were entered into a Microsoft®Excel spreadsheet and any discrepancies resolved by visual inspection to ensure data-entry accuracy. Descriptive statistics and simple correlations were computed for responses to all Likert scale questions, and frequency-of-response was tabulated for all open-ended questions.